Prior to planning any process expansion project, it’s important to perform a thorough process review and evaluation. We've written up a case study of our work with a client where this proved particularly helpful, and have outlined specific issues we found when performing this review. We were able to identify weaknesses, inefficiencies, as well as gauge the impact that an expansion would have on their overall process.
Process Review Evaluation Case Study
The client manufactures electron beam emitters to sterilize products and packaging, improve the performance of plastics and other materials, cure inks and coatings, and eliminate pollution. They are considering a significant process expansion, and hired us to perform a review and evaluation of their chilled water systems to answer questions regarding current operational issues and the impact of the expansion. Below are the highlights of the report we developed for them.
What We Found
We found a number of important issues relating to the chilled water system which could affect their expansion:
- A Piping System Inspection revealed that the system was significantly different than shown on the client’s as-built drawings.
- An inspection of the installed equipment revealed that there were some significant pressure drops in at the chilled water loads, which could affect the chilled water supply and distribution specifications required in an expanded system.
- We discovered a surprising pressure drop (120 PSI) caused by the small diameter of the cooling coils in one of their cooling load types. This would could cause problems in expected cooling cycle once they expand the number of these loads on the system.
Based on our findings we drew several conclusions as to how much affect the different issues could have on their expansion:
- The chilled water piping system is adequate, in size and capacity, to service the planned expansion. However, there may be a required change in piping size, depending on the selected location of the new process loads and load types.
- A water treatment program needs to be instituted to properly dose the closed loop chilled water system system with oxygen scavengers & corrosion inhibitors. Replacing the entire piping system with PVC will help with the water quality issue, but will not entirely eliminate the need for a water treatment program.
- Base chiller cooling capacity is adequate to accommodate planned expansions.
- We determined that the system functions without make-up water because of the presence of a closed ball. This make-up volume is critical because without it, the return pressure drops below atmospheric causing a vacuum in the return header system.
- We noted that the discharge pressure controller has a number of problems, including: Incorrect display readings, incorrect pressure transducer range, and incorrectly sized and located bypass pressure control valve.
Based on our findings and conclusions we were able to make a series of process recommendations which will help eliminate problems when the client moves forward with the expansion project. These recommendations included:
- Establishing and maintaining a third party water treatment program.
- The addition of pressure control valves at headers to specific load areas.
- Replacing the entire chilled water carbon steel piping system with PVC.
- Removing all unnecessary pressure drops by removing all drop circuit setters, all subheader circuit setters, and circuit setter at pump discharge in the chiller room.
- Replace Bypass pressure control on the system to VFD Speed control of water pressure.
- Replacing and relocating pressure transmitters and adjusting pressure controller ranges.
Performing a thorough process review prior to planning a chemical process expansion project can help ensure you are using the right equipment and help catch any problems with your process and include the improvements in the expansion. Identifying weaknesses and inefficiencies prior to an expansion means these problems can be fixed before or during the expansion, rather than encountering bigger problems down the road. Gauging the impact an expansion will have on the process is vital to ensuring your expansion addresses all your needs.